package org.gry.dy20180724;


public class Yuan {

	double r;
	
	public Yuan(double r) {
		this.r = r;
	}
	public void zhouChang() {
		double chang = 2 * Math.PI * r;
		System.out.println("2*"+"3.14*"+r+"="+chang);
	}
	public void mianJi(double r) {
		
	}
	public static void main(String[] args) {
		Yuan yuan = new Yuan(5);
		yuan.zhouChang();
	}
}
